recuperate a characteristic 's value from a Nordic device

RE: recuperate a characteristic 's value from a Nordic device

Hung Bui — Tue, 21 Apr 2015 10:39:46 GMT

@rosa: You can try to test with the Master Control panel app on the phone.

I would suggest you to test and have a look at the source code of either the nRFToolbox - heart rate profile, or the nRFUART. In both apps we receive notification and display it on the app.

RE: recuperate a characteristic 's value from a Nordic device

rosa — Tue, 21 Apr 2015 08:03:30 GMT

@Hung Bui : the server is sending a notification to the mobile, i can verify this by the master control (using a dungle) but the application is not notified yet , i'm looking for the best function that can detect the new Major's value

RE: recuperate a characteristic 's value from a Nordic device

Hung Bui — Tue, 21 Apr 2015 07:43:11 GMT

@rosa: When the characteristic changed the value locally (on the server), it's not possible for the client (the phone for example) to know that. You would need to notify the client by sending a notification from the server to the client. When the client receive the notification, you will have onCharacteristicChange callback. You can have a look at our ble_app_hrs example where we notify the heart rate measurement and the battery level.

RE: recuperate a characteristic 's value from a Nordic device

rosa — Mon, 20 Apr 2015 14:55:16 GMT

thanks for your answer ulrlich but i'm sorry maybe i didn't explain my question very well, in fact i'm able to read the characteristic's value from the Nordic device, but when the device changes it , the application is no more able to read the new value . what should i do then ? My method to read the major's characteristic is

public void readMajorCharacteristic() {

	if (mBluetoothGatt == null)

		return;

	if (mMajorCharacteristic != null) 

		mBluetoothGatt.readCharacteristic(mMajorCharacteristic);
}

but this method is reading the located value to the application ...

i think it's something related to a BluetoothGattCallBack or onCharacteristicChange maybe but i'm not really sure what can it be

RE: recuperate a characteristic 's value from a Nordic device

Ulrich Myhre — Sat, 18 Apr 2015 19:44:27 GMT

Hi,

You have to send a read request to the remote characteristic to fetch its latest value. This is done with the readCharacteristic (BluetoothGattCharacteristic characteristic) API call in Android. The operation will then call onCharacteristicRead once the remote value is read. Please refer to the documentation for BluetoothGatt [0].

This, and more, is also explained in the Android BLE tutorial at [1]. If you familiarize yourself with everything on that single page, I think that will clear up a few things for you.

[0] developer.android.com/.../BluetoothGatt.html

[1] developer.android.com/.../bluetooth-le.html